Electrical recorder



Dec. 8, 1931. s wlLLlAMS 1,835,737

ELECTRICAL RECORDER Filed Jan. 29, 1931 IN VE N TOR 5.3. WILLIAMS Patented Dec. 8, 1931 UNITED STATES SAMUEL n wrLLIA vrs, or 3300mm; NEW YORK, nssrclv'on T BELL 'rnnnrnonn,

LABORATORIES, :INCORPORA'IED, OE NEW YORK, N. Y A CORPORATION OF -NEW 4 YORK ELECTRIGAL sme ma Application filed January 29, 193.1. s riaino; 512,934; H I i This invention relates to electrical counting systems and is particularly adapted foruse in a telephone system. i

In general, the invention may be described as an integrating timing'circuit, since its object is to produce a composite and single record of the number of simultaneous occurrences ofa certain event counted at a particular time, the count being repeated at frequent and regular intervals. In the embodiment of the invention disclosed the event is the use of a telephone trunk circuit and is manifested and illustrated by the closing of a contact point. By counting the number of such contacts simultaneously closed at a given time by repeating this operation at frequentand regular intervals, a record ofthe integrated holding time: of a group of. trunks maybe obtained. 7 V

'A' feature of the invention a plurality of circuits each having a fixed resistance and a contact point and all terminating in a common connection to form one arm of a heatstone bridge which is balanced automatically by the movement of a step-by-step's'witchand which in turn controls a counting mechanism. In the drawings:

Fig l is a circuit diagram of one embodiment of the present invention; and

Fig.2 is a schematic diagram showing how certain elements of the system shown in Fig. 1 constitute a Wheatstone bridge arrangement. Q

In the operation of this electrical recorder a clock 1 controls a pair of contacts 2 and 3 periodically. Therefore, periodically the relay 4 will be energized for a short interval of time. Upon the energization of relay 4, relay 5 will be released from its operated condition in which it is left each time the recorder operates as will be understood from the following description. In the present embodiment of this invention it is desired to count the number of trunk circuits which are busy at any particular time and to do this periodically. Each such circuit is represented by a relay 6. When such circuit is busy the relay 6 will be energized and ground will be connected through its front contact and armature through a re sistanceT tothefrwinding of relay 7 ;Whn it one for more of relays are energized'g'round connected throughjtheresistanceszT inxparal- 7 to battery causes the: energization of this ,lel and thence through the winding of' relay relay. Relay 7*inresponding connects battery throughresistance R to switcharm'8 and in parallel therewith through the winding of polarized relay 9 to th junction between resistances T and the winding of relay 7. 5

A- connection is nova established from switch arm 10, back contact" and. right hand armature of relay 5 (assuming that relay 5 has been returned to normal through the action of clock 1) to'the'winding ofrelay 11. Relay 11 becomes energized and closes a circuit from battery, the winding of relay 12, the front contact and outer right hand armatureof relay 11, armature and back contact of stepping magnet 13 to ground. Belay12 becomes energizedinthis circuit and through 1 its right hand armature establishes a by-path fromits wind-ing to the armature ofstepping magnet '13 independent of the hand armature of relay 11. 4

Through its lefthand armature, rela 1'2 establishes a circuit from battery, win ing of stepping magnet 13, lefthand armature and front contacts'of relay 12, innermost right handarm'ature andfront contact of 'relayll through the two'windir'i'gsfof register 14: to ground; The register has two windings resistances. The resistance of this circuit is too great to allow the energization of step-- ping magnet 13, but itdoes cause the energization of register 14 Upon the 'comple marked H and L to designate high and low tion of its step, register 14 short-circuits its high resistance winding andthus reducing the resistance in the circuit just described, causes the energization of stepping magnet 13.- When the stepping magnet'13 becomes energized it o'pens'the circuitl fo'r relay' 12 and this relayreturns to normal: The circuit of stepping magnet 13 is now broken an'd it in turn returns to normal thereby reestablishing the original energizing 'circuit for relay 12. I i i c," 1

' Upon the deenergization of stepping magnet 13, the switcharr'ns 8 and 10 are moved to their first active contacts whereupon the original energizing circuit for relay 11 is opened and a circuit established from switch arm 10 through the contact on which it now rests, the middle right hand armature and front contact of relay 11, the front contact and armature of relay 9,,winding of relay 11 to battery so that relay 11 is maintained energized under the control of relay 9.

'Switch arm 8 now connects resistance S in circuitso that if a corresponding number of relays 6 are energized the Wheatstone bridge will be balanced and polarized relay 9 will be deenergized. If a balance is not achieved at this time then stepping magnet 13-'becomes energized again and the switch armi 8 is-moved until aproper resistance to balance the number of busy .circuits has been found When the Wheatsto'ne bridge is-balanced then relay 9 becomes ,deenergized, and

consequently relayll is returned to normal.

winding of relay 5.

this time a circuit is established from switch arm 10 through the vcontact on which it rests, the middle right hand armature and back' contact of relay 1 1, the normal contact of the inner-left hand armature of relay 5, back contact and armature of relay 4, winding ofrela-y 5 to battery. Relay 5 now looks in a circuit from ground, inner left hand armature andfrontcontact of relay 5, back contact and armature ofrelay 4 to the Through its middle left hand armature, relay 5 causes the actuation of register 15. This register counts the number of timesrelay '5 operates and therebychecks the operation of the clock 1.

5, however, is maintained in its operated position until the clock 1 closes contacts 2 and 3 momentarily to cause the momentary operation of relay 4. 7 v

Through the operation ust described, register 14 counts the number of steps which it takes the switcharm 8 to move in order to check the number of circuits represented by the relays 6 which are operated. The reg-- ister 16 counts the number of steps which it takes the switch arm'8 to move to return to normal after a balance of the Wheatstone bridge has been achieved. The sum of the readings of the message registers 14 and 16 will therefore. be the total number of steps which it takesthe switch arm 8 to move through a complete cycle of operation. Only one message register such-as 14 is actually needed but the second one 16 may be used as a check.

Over a long period of time the reading of message register 14 divided by the reading of message register 15 will give the average number'of circuits busy. Alsoover a long period of time the reading of message register 14 will give a substantially correct indication of the total time over which the circuits represented by the relay 6 are busy when such reading is properly interpreted in view of the periodicity of the action of relay 4 controlled by the clock 1.

What is claimed is :7

1; In an electrical counting system, a plurality of circuits terminating in a common connection, a contact point, in each of said circuits said contact points being in number variably closedat different times and means for counting andrecording the number of said circuits closed at anytime.

, 2. man electrical counting system, a plurality of circuits terminating in acommon connection, a fixed resistancev and a contact point ineach of said circuits, said contact points being in number variably closed at difi'erenttimes, and means including an automatically adjustable VVheatstone bridge for counting and recording the number of said circuits closed at any time. s

3. In an electrical counting system, a plurality of circuits terminating in a common connection, a contact point in each of said circuits, said contact points being in number variably closed atdifierent times, means for counting and recording the number of said circuits closed at any one time and means for periodically 7 operating said counting and recording means. i i i 4; In an electrical countingsystem, a'plurality of circuits teiniinating'in a common connection, a contact point in each of said circuits, a fixed and equal resistance in each of said circuits, said contact points being in number variably closed at different Ttimes,fa variableresistance and a step-by-step switch for controlling said variable resistance, and means including said plurality of circuits, said variable resistance and said step-by-step switch comprising a Wheatstone bridge for automatically counting and recording the 1 number of said circuits closed at any time.

5. In an electrical counting system, a plurality of circuits terminating in a common connection, a contact point in each of said circuits, a fixed resistance in each of said circuits, said contact points being'in number variably closed at different times, a variable resistance and a step-by-step switch for controlling said variable resistance, means including said plurality of circuits and said variable resistance comprising a Wheatstone bridge'for automatically setting said stepby-step switch 'in a position corresponding to the numberrof said circuits closed at any time, and means controlled by said step-bystep switch for counting and recording the said number of said circuits closed at any time.

In witness whereof, I hereunto subscribe my name, this 28th day of January, 1931.

SAMUEL B. WILLIAMS. 

